The title complexes have been synthesized and characterized by UV, IR, low angle X-ray diffractometry, TG-DTA analysis and mole conductometric analysis. The surface pressure-area isotherm (π-A) behaviours of these complexes were investigated. The zero-pressure molecular area obtained for the complexes of La, Nd, Dy and Yb are 1.94, 1.93, 1.73 and 1.85nm^2 permolecule respectively, which is much larger than the value of 0.55nm^2 calculated according to structural data for Eu(TTA)~4^-. This indicates that the anion and cation of the complex may take a "shoulder" to "shoulder" arrangement on the substrate, and the angle between the alkyl chain and substrate may be very small.

Key words: SYNTHESIS, CHARACTERIZATION, COATING